The most important factor which limits the speed of present day freight trains is not so much the curves in the roadbed as was true in the earlier days, but rather the misalignment of the tracks. Over the past thirty years most railroads have been forced to cut down on their efforts spent in maintaining the alignment of their tracks. Consequently most of their roadbeds and tracks have gradually gotten badly out of alignment merely due to the passage of trains thereacross. Once a track is seriously out of alignment, the speed at which a train may travel on those tracks without leaving the track is diminished. Rather than improving the problem by increasing the maintenance effort to maintain the tracks in better alignment, most railroads have been forced to merely slow the speeds of their trains across those misaligned tracks. When the freight cars are fully loaded, the problems of side-sway due to badly aligned tracks is not as severe as the situation with empty cars. Trains speeds with empty cars must be substantially reduced on poorly aligned tracks from those speeds when fully loaded because the empty cars have a greater tendency to side-sway and jump the track. The newer jumbo-sized railroad cars further compound this problem to the point where some empty trains must literally crawl across certain sections of track to prevent the cars from severe side-sway and ultimate derailment.